1. DO NOW In science binder, date the next page and answer the question:
How do we know from looking at the Periodic Table how many electrons an atom has? (hint: use p 10-11of INB)
If you finish early, please make sure your table of contents is up to date in your INB.

2. Answer to Do Now
How do we know from looking at the Periodic Table how many electrons an atom has?
We look at the atomic number, which tells us the number of protons. In an atom, the number of electrons is the same as the number of protons.

3. atom proton neutron electron electron shell (energy level)
Vocabulary Refresher
atom
proton
neutron
electron
electron shell (energy level)

4. Vocabulary Refresher
atom – smallest object that can retain the properties of the element
proton – positive charge, in nucleus
neutron – no charge, in nucleus
electron – negative charge, orbits the nucleus of an atom
electron shell (energy level) – where electrons orbit the nucleus

5. Today’s Agenda
Listen to song/Watch a video on the atom (look at structure of atoms)
Discuss the structure of atoms
Build a human Bohr model the classroom
Construct a Bohr Model
Finish up our element research projects

6. Song/Video Meet the Elements - Lyric Sheets for Binders
Video – Look at the structure of the atom while watching, note where the protons, neutrons and electrons go

7. Bohr Models
What is a Bohr model? The Bohr model shows that the electrons in atoms are in orbits around the nucleus. It also shows the protons and neutrons contained within the nucleus.

8. Helium atom
Helium is in period 1 (row 1 of Periodic Table)so it contains 1 electron shell. It has 2 protons, 2 neutrons and 2 electrons

9. Found on Page 10 of your INB

10. electron shell # of electrons 1 2 2 8 3 8 4 18
Electron shells
electron shell # of electrons

11. Steps to Create a Bohr Model
Found on page 12 of your INB!
Determine the number of protons, neutrons and electrons (from Periodic Table - pages 10 and 11)
Draw a nucleus with the correct number of protons and neutrons inside
Determine how many electron shells are needed (by row in periodic table 1st row is 1, 2nd row is 2, 3rd row is 3)
Draw circles around the nucleus to represent electron shells (1 for each shell)
Place the correct number of electrons in each shell (1st shell can only hold 2 electrons, 2nd shell can only hold up to 8)
LABEL YOUR ATOM (indicate the name of your atom)

12. Guided Practice
In order to draw Bohr models of these elements, you must first determine the number of protons, neutrons, and electrons. Once you have found this information, follow the directions to draw your model.
Protons: _____ Neutrons: _____ Electrons: ______
How many energy shells will this have? ____
How many outer electrons does this element have? __4__
Bohr Model: 6 6 6 6 C
Carbon
12.0 2

13. Guided Practice
What element is this? How do we know?

14. Human Bohr model
We are going to construct a human Bohr model of Carbon in our classroom
You will be an electron orbiting the nucleus
We will construct a carbon atom
Electron shell 1 has green marks over tape
Electron shell 2 has orange marks

15. Paper plate Bohr model
Construct a Bohr model of your element using pens, pom poms and a paper plate
Red pom poms = protons
Yellow pom poms = neutrons
Blue pom poms = electrons
Draw a nucleus
Draw electron shells
Glue protons, neutrons and electrons

16. Exit Ticket What does the atomic number of an atom represent?
In an atom, what is the relationship between protons and electrons?
Why would the Bohr model be called a planetary model of the atom? For a ticket!!!

17. Atomic Math
Challenge

18. Use the information provided to answer the questions.
5 B Boron 11
2 He Helium 4
11 Na Sodium 23
17 Cl Chlorine 35
What is the atomic number for Chlorine?
What is the atomic mass for Boron?
How many protons are in an atom of Na?
How many neutrons are in an atom of He?
How many electrons are in an atom of Cl?
How many protons and neutrons would be in an atom of Chlorine?
How many protons and neutrons are in an atom of Helium?

19. The answers are … What is the atomic number for Chlorine? 17
5 B Boron 11
2 He Helium 4
11 Na Sodium 23
17 Cl Chlorine 35
What is the atomic number for Chlorine?
What is the atomic mass for Boron?
How many protons are in an atom of Na?
How many neutrons are in an atom of He?
How many electrons are in an atom of Cl?
How many protons and neutrons would be in an atom of Chlorine?
How many protons and neutrons are in an atom of Helium? 17 11 11 2 17 35 4